What is stereographic method?

Stereographic projection is a method used in crystallography and structural geology to depict the angular relationships between crystal faces and geologic structures, respectively. We orient the crystal such that the pole to the (001) face (the c axis) is vertical and points to the North pole of the sphere.

How would you describe a Stereonet?

Stereonets are a graphical tool representing the hemisphere of a globe, used for presentation, analysis and interpretation of three-dimensional directional data such as planes and lines.

What is the meaning of stereographic?

Definition of stereographic : of, relating to, or being a delineation of the form of a solid body (such as the earth) on a plane stereographic projection.

What are stereographic projections used for?

Stereographic projection is a technique for displaying the angular properties of a plane faced object on a single drawing or diagram. Directions as well as planes may be shown and any desired angle can be measured directly from the projection using a graphical technique.

How do you calculate stereographic projection?

The stereographic projection of the circle is the set of points Q for which P = s-1(Q) is on the circle, so we substitute the formula for P into the equation for the circle on the sphere to get an equation for the set of points in the projection. P = (1/(1+u2 + v2)[2u, 2v, u2 + v2 – 1] = [x, y, z].

What do Poles represent on a stereonet?

This special line is called the pole to the plane. Plotting up poles to planes represents the planes as points on a stereonet instead of as great circles. Geologists often plot poles to planes instead of the actual planes because it makes it easier to look at a large amount of data.

What is Streography?

Definition of stereograph : a pair of stereoscopic pictures or a picture composed of two superposed stereoscopic images that gives a three-dimensional effect when viewed with a stereoscope or special spectacles.

What is the meaning of Gnomonic?

Definition of gnomonic 1 : of or relating to the gnomon of a sundial or its use in telling time.

What is a Stereonet on a graph?

A stereonet is the plane of projection of the lower half of this sphere – it is a lower hemisphere graph. Imagine a plane cutting through the centre of a lower hemisphere (figure 1a). The stereonet forms the surface of this lower hemisphere.

What is an equal-area stereonet?

Stereographic Projection Equal-area stereonets are used in structural geology because they present no statistical bias when large numbers of data are plotted. On the equal-area net area is preserved so, for example, each 2 degrees polygon on the net has the same area.

How are stereonets used in geology?

Stereonets are used in many different branches of geology and can be used in a range of ways beyond those which are discussed here (see references for further uses). Stereographic projection involves plotting 3D data (planar or linear) on to a 2D surface (stereonet) where it can be manipulated and interpreted.

What is a great circle on a stereonet?

For a plane (e.g. a discontinuity surface), its intersection with the lower half of the reference sphere defines a unique line on the stereonet (in the shape of a circular arc called a “ great circle”. To plot the great circle, the dip di rection and dip must be known. Wyllie & Mah (2004)